Asymmetric chip design for LEDS

Abstract

The area of a surface-emitting LED is reduced, and hence the number of LEDs which can be obtained from a single wafer is increased, by a chip design in which the light-emitting spot is positioned asymmetrically toward one corner of the chip. Preferably, an L-shaped contact is formed on the light output surface so that light-emitting spot emerges from between the legs of the L.

What is claimed is: 
     
       1. A light emitting diode comprising a semiconductor body which has essentially the shape of a parallelipiped having first and second opposing major surfaces, said body including an active layer for generating optical radiation in response to the flow of electrical current therethrough, and   means for causing the radiation to emerge from said active layer and through said first major surface as a beam in a direction essentially orthogonal to said active layer,   characterized in that   said causing means for causing said beam to emerge from a region positioned in only one quadrant of said parallelipiped.   
     
     
       2. The diode of claim 1 wherein said causing means includes on said second major surface a dot-shaped electrical contact which is positioned in only said one quadrant of said parallelipiped. 
     
     
       3. The diode of claim 2 wherein said causing means includes on said first major surface a lens which is positioned essentially in registration with said dot contact. 
     
     
       4. The diode of claims 2 or 3 further including on said first major surface an L-shaped contact positioned so that said beam emerges from between the legs of the L. 
     
     
       5. The diode of claim 4 wherein said dot contact is positioned in said one quadrant and said L-shaped contact is positioned in the remaining three quadrants. 
     
     
       6. The diode of claims 1, 2 or 3 wherein said body includes a plurality of layers forming a double heterostructure. 
     
     
       7. The diode of claim 6 wherein said heterostructure comprises layers from the GaAs/AlGaAs materials system. 
     
     
       8. The diode of claim 6 wherein said heterostructure comprises layers from the InP/InGaAsP materials system. 
     
     
       9. A light emitting diode comprising a Group III-V compound semiconductor body which has essentially the shape of a square parallelipiped having first and second parallel major surfaces, said body including a double heterostructure which comprises a pair of opposite-conductivity-type cladding layers and an active layer sandwiched therebetween and essentially lattice-matched thereto,   contact means for forward biasing said diode and for applying thereto electrical current which causes said active layer to generate optical radiation in the form of a beam which emerges through said first surface, said contact means comprising   a dot contact formed on only one quadrant of said second surface, and   an L-shaped contact formed on the remaining three quadrants of said first surface, and   a heat sink thermally coupled to said diode through said second surface.   
     
     
       10. The diode of claim 9 further including a Group III-V compound substrate, said heterostructure being formed on one major surface thereof and the other major surface of said substrate being said first surface,   said substrate having a cavity in said first surface and an integral lens formed at the bottom of said cavity in essential registration with said dot contact.